求翻译：2、每天保证2小时以上的通风，既可以维持室内良好的空气流通，又可以有效防范甲醛挥发对人体的伤害。是什么意思？

2 guarantee more than 2 hours a day, venting, can maintain good air ventilation, volatile formaldehyde and can effectively guard against harm to human body.